Hello all

The issue I have is that on occasions, I brake to stop but the car seems like it doesn’t want to stop – dangerous.

First, I thought the brake wasn’t working

After a few more experiences, I thought that the multitronic was occasionally delaying shifting gear and applying more positive drive than I’m used to

Upon further occasions and closer monitoring, I now think that the accelerator is sticking which makes sense as it feels like I’m fighting a level of torque when braking (also feels like the brake pedal is stiff or stuck).

Did some tests in neutral
Press the accelerator lightly so that it reaches 1250rpm, release accelerator and observe revs
1. Most of the time, the rev counter goes back down to 750rpm
2. On occasions, it stays at 1250rpm (like it was in cruise control or something) until the brake pedal is pressed (first touch of brake does nothing, must apply strong force to overcome accelerator and then it sounds like its about to stall but resides back to 750rpm
3. On occasions, even though I press the accelerator the same amount – revs go up to 2500rpm, a little inconsistent and gives the car a bit of a jolt sometimes

Anyone know a likely cause of this – throttle body sticking, accelerator cable, electronics, or hopefully not the multitronic gear box?

Regards

 

What year is your car? Engine type?

 

check all vacuum lines and make sure they are all connected.

 

Its a 2003 1.9 TDI

Just noticed that the cruise control switch was in the on position. Havn't had the issue since but its only been one day.

I'll ask my mechanic to check the vacuum lines - I wouldn't know where to look

Thanks

 

On my 2001 US spec A6, there is a vacuum diagram printed on the underside of the hood/bonnet. There should be one on yours to I would imagine...

If the problm comes back, then check the throttle body for any objects or residue. Then check for any vacuum leak.

 

Hi again

Issue reapperaed so I had the mechanic take a look at it while he was installing a towbar. He took it for a test drive and of course there was no sign of the problem. He checked the vacuum lines and throttle body and said everything was OK suggesting that the issue was electronic and not mechanical. It happens at least once a week.

He did note a delay in the accelerator kicking in when taking off from a standstill (ie you press the accelerator, 2 seconds later - acceleration begins) - I noticed this too but read somewhere that this is normal for the multitronic transmission - anyone know, is it normal?

Guess I should probably try and get a vagcom reading somewhere - there are no issues on the dashboard screen though.

Regards

Dew Vou

 

Just to add to this, on the way home in traffic - I was at a standstill, the engine idleing at 800rpm in drive mode, my foot on the brake pedal - engine then decides to increase revs to 1200rpm with no input from me - weird. Also, to move forward at 5mph on flat ground, the engine had to go up to 2000rpm. When applying the brake to stop again, it feels like the gearbox goes up a gear. Would it be possible that the gear box is confused about what gear its in, that maybe it thought it was moving down to second where it actually moved up to second?

Regards

Dew Vou